Air assist atomization of the liquid fuel injected from the nozzle of a fuel injector is a known technique that is used to promote better preparation of the combustible air/fuel mixture that is introduced into the combustion chambers of an internal combustion engine. A better mixture preparation promotes both a cleaner and a more efficient combustion process, a desirable goal from the standpoint of both exhaust emissions and fuel economy.
The state of the art contains a substantial number of patents relating to air assist atomization technology. The technology recognizes the benefits that can be gained by the inclusion of special assist air passages that direct the assist air into interaction with the injected liquid fuel. Certain air assist fuel injection systems use pressurized air, from either a pump or some other source of pressurization, as the assist air. Other systems rely on the pressure differential that exists between the atmosphere and the engine's induction system during certain conditions of engine operation. It is a common technique to mount the fuel injectors in an engine manifold or fuel rail which is constructed to include assist air passages for delivering the assist air to the individual injectors.
The state of the art that is presumptively known to the Applicants is represented by the file of commonly assigned U.S. Pat. No. 5,174,505 (J. J. Shen, 29 Dec. 1992) which relates to a disk-type atomizer containing a single disk within a shroud that is fitted over the nozzle end of the fuel injector. While the present invention utilizes the same type of disk as disclosed in U.S. Pat. No. 5,174,505, and also possesses the advantages of that patented fuel atomizer, the present invention is distinguished by the use of a stack of plural disks in which the air assist openings of one disk are circumferentially offset from those of another disk whereby assist air is directed radially inwardly at locations that are both axially and circumferentially offset from each other. The objective of the present invention is toward still further improvement in fuel atomization by the action of the assist air streams on the injected fuel causing further fuel shearing that further reduces fuel particle size.
Further features, advantages, and benefits of the present invention will be seen in the ensuing description and claims which are accompanied by drawings. These drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at this time for carrying out the invention.